Official HTC One M8 Android 5.1 update is not expected soon, but if you want to run the 5.1 update on your international M8 set right now, you can. That’s all made possible by the excellent development community of users, which churn out custom ROMs day after day. Today, CyanogenMod 12.1 was released for the One M8, which is based on Android 5.1 and brings home some of its own cool set of features too.

You need to do some pre-requisite things first, like unlocking the bootloader and installing the TWRP recovery to be able to install a custom ROM like CM12.1. Of course, if you have not done that already because if you are reading this, chances are that you have done so already. Anyway, we’ve got required links below.

What about official update release?

HTC could be shooting the One M8 Android 5.1 OTA update in your direction sometime in May or early June. That’s not far really, but it’s far from close. We expect HTC One M9 to receive the 5.1 update first, and One M8 some 1 month after that. Currently, there are no signs of One M9 5.1 update either.

Benefits and drawbacks of the unofficial update

Lots of benefits of installing a custom ROM. First of all, the reason we’re talking all this: latest Android OS, 5.1 update. Then, you’ve got new features and customization options including system-wide theming from roms like CM12.1. And there are many more features that you’ll find so cool, and dependable, that it prove would going one generation back when installing an HTC firmware, or simply comparing your favorite custom ROM to HTC’s stock ROM.

On the drawbacks side, you have to do some labor to be able to install custom ROM, which begins with unlocking bootloader, which enables you to install custom recovery like TWRP and CWM, a must for installing a custom ROM. And, the thing is, you lose your device’s warranty when you unlock bootloader or simply said, root your device or install custom recovery. But it’s totally worth it, and is really once in a life achievement.

Removing the unofficial update?

You can install official firmware back, which will bring the device back to factory state, and will remove your custom recovery and ROMs along. Though, you may not get your warranty back.

Note: You know, because this ROM is not an official HTC Android 5.1 update for One M8, there are chances you could find few kinks at some of its corners. Any major bugs will be reported below.

HTC One M8 Android 5.1 Lollipop update

NOTE: When downloading a ROM, do check its development page first for newer and more stables builds, if any available, with less bugs. Since the 5.1 ROMs are under heavy development, consider this a must.

More Android 5.1 based ROMs to be added as and when available.

Supported devices

HTC One M8, international version

Don’t try on One M8 sets at Sprint, T-Mobile, Verizon or AT&T

Don’t try on any other device whatsoever

Instructions

Warning: Warranty may be void of your device if you follow the procedures given on this page. You only are responsible for your device. We won’t be liable if any damage occurs to your device and/or its components.

Important Note: Backup important files stored on your device before proceeding with the steps below, so that in case something goes wrong you’ll have backup of all your important files.

Transfer the ROM file and Gapps file to your device’s internal storage and remember the location where you save them.

You need TWRP recovery for this. Get the latest recovery’s .img from here. Then see this page for help with installation.

Boot into Recovery mode.

Make a backup. Once in TWRP recovery, take a backup of your current ROM. Select Backup, then do a “Swipe to Back Up” on the bottom of the screen. Wait for the backup to finish, it’s a time consuming process.

Wipe your device. Once the backup is finished, do this: tap on Wipe, then Advanced wipe, and then select Cache, Dalvik/ART cache and Data. Then do the “Swipe to wipe” at bottom to ready the device for ROM flashing by erasing the cache, dalvik cache and data in one shot.

Install ROM now. Go back to the main menu of TWRP recovery and select Install. Navigate to the file where you saved your ROM’s zip file, select it and “Swipe to Confirm Flash” on the bottom of the screen. Now wait until the flashing process finishes.

Also install the Gapps the same way as ROM.

Go to back to recovery’s Main menu, select Reboot » select System.

Your device will now reboot with Android 5.1 update!

In case you need any help over this, let us know. And, you can thank the developer for creating the ROM.